Electromagnetic properties of chloroprene rubber after long-term ultraviolet ageing, oil immersion and thermal degradation

The electromagnetic properties of chloroprene rubber after long-term ultraviolet ageing, oil immersion and thermal degradation were experimentally investigated in the frequency range from 1 kHz up to 1 THz. Ageing was shown in terms of mechanical degradation and the change in the complex dielectric permittivity. Within the whole investigated frequency range decrease of dielectric permittivity was observed after thermal treatment combined with oil immersion in comparison with chloroprene rubber stored under normal conditions. In contrast, thermal and ultraviolet ageing without immersion leads to increase of rubbers dielectric permittivity in all investigated frequency ranges. A non-invasive express method of degradation detection is proposed and proofed.